Mary Tyler Moore, former costar of Valerie Harper, reacted emotionally to the news of her good friend's malignant brain tumor.

Best friends as their characters in the Mary Tyler Moore Show, Moore and Harper have been best friends in life as well. Since the show was on the air over four decades ago, the comedic duo has remained close.

“I’m absolutely devastated by this news,” Moore told People. “Valerie has given so much joy, laughter and love to the world. I join her fans and send much love and positive thoughts to her and her family during this difficult time.”

Harper had called Moore prior to making her grim diagnosis public. Moore is no stranger to health scares. Just two years ago she underwent surgery for a benign tumor in her brain, and she’s publicly struggled with diabetes. When Harper told her the news she said, “Val, I’m so sorry,” according to Harper.

In the past, it’s been Harper who has been there for Moore, who in addition to her own health issues, lost both her sister and son in untimely deaths. "In one of her books she said, 'At every funeral of my family, Val was at my side,'" says Harper. "It's true. I love her."

Like Moore, actress Roma Downey, who worked with Harper on Touched By An Angel, shared her love for Harper, telling EXTRA, “We’re going to keep her in our prayers. I love Valerie, I love working with her. She is a beautiful, wonderful, generous hearted woman.”